Project 2 attempts to elucidate mechanisms associated with amyloid production and deposition in the aged and Alzheimer brain and to document the effects of excessive amyloid accumulation on metabolic processes necessary for cellular survival. Brain tissues will be subjected to analysis with monoclonal antibodies to various amyloid precursor region and with corresponding nucleotide probes for in situ hybridization studies. Staining patterns will be visualized and quantified by compute enhanced imaging procedures. Synthesis and accumulation of amyloid will be evaluated with regard to senile plaque formation. The effects of amyloid elaboration on brain cell survival will be examined by assessing the consequences on key metabolic processes at the levels of transcription, translation, and RNA metabolism. Evaluations will be made by antibody probes to RNA polymerases, ribosomal proteins, ribonuclease regulatory protein and a neural-specific membrane component. The effect of amyloid accumulation on neuron-specific and glial-specific markers will be assessed. These data will be correlated with electron microscope analysis of individual cells and morphometric analysis of neuronal and glial populations. Ultimately the transgenic mouse will be examined by the above-described analytic procedures not only to elucidate aspects of amyloid production and turnover, but also to document the extent to which an animal model is a suitable vehicle for the study of amyloid deposition in the AD brain. These studies will complement the molecular genetic characterization of transgenic mice proposed in Project 1. Based upon the data to be derived from the proposed studies, we shall attempt not only to define mechanisms to explain the excessive accumulation of amyloid during normal aging, in AD, and expectedly in the transgenic mouse, but also to document the consequent effects of this process on cell survival and death.